Because of its physical resistance to heat and chemicals, asbestos has been a major component of building materials for a number of years. During the period from 1950 to 1974 in the United States, thousands of tons of asbestos-containing material (ACM) was sprayed into buildings to provide fireproofing and acoustical insulation. ACM was also applied as thermal insulation for water pipes and heating and ventilation ducts.
ACM is typically a composite dry mixture which includes asbestos fibers and particles. The mixture is sometimes coagulated by a glue-like binder which also bonds the material to surfaces such as ceilings, walls, floors, and beams. Asbestos itself was also used as a binder in building materials because the asbestos fibers have good cohesive and adhesive properties.
It is now well known that exposure to airborne asbestos poses serious hazards to health. In particular, exposure of friable (easily crumbled) asbestos has been linked to diseases such as asbestosis, mesothelioma, and cancer of the lung. To reduce the frequency of exposure to asbestos, most forms of ACM are removed whenever buildings are re-modeled or renovated.
Procedures for the removal of are set forth in EPA Regulations (40 CFR, Part 61, Subparts A & B, 1973). Among these procedures are the important aspects of protecting the workers engaged in removing the materials, minimizing airborne asbestos concentrations during removal, and controlling and collecting the removed materials.
The process for removal of sprayed on asbestos-containing materials typically begins by wetting the materials using various well known wetting agents. The next step is to manually scrape the surface using metal scrapers such as those used for removing paint and tile. After gross removal of asbestos-containing materials by scraping, residual material is further removed by scrubbing with brushes and pads and the like in a process known as "detailing". The standard for detailing is removal of all visible asbestos containing materials. After detailing the surface, the removed asbestos-containing material is collected using shovels, squeegees, mops, and the like. Vacuums have also been used to collect removed asbestos-containing materials from the work site.
A variation of the removal process is to use high pressure water blasting ("hydroblasting") of the asbestos-containing materials which can achieve faster removal. However, hydroblasting has the following drawbacks:
1. Hydroblasting results in large amounts of asbestos contaminated waste on the jobsite which greatly increases the likelihood of water leaks which can cause water damage and contamination outside the work areas. PA1 2. The high pressure water causes an explosive disturbance of the asbestos material which results in significant increase in asbestos fibers suspended in the air of the work area and consequent increased exposure to workers. PA1 3. Hydroblasting can cause serious physical injury and has on jobsites caused loss of limbs, fingers and nearly decapitated a worker. PA1 4. The force involved in hydroblasting can cause a breach in containment and can drive asbestos materials into areas adjacent to the work area as well as impact asbestos into difficult access areas where the asbestos may cause exposure in the future. PA1 5. Hydroblasting greatly scatters the asbestos containing material often to locations in and around fixtures such as pipe hangers where it previously wasn't applied.
From the above description, it can be appreciated that the removal of asbestos-containing materials (or any materials bonded to a surface) is a long, tedious, expensive, and hazardous undertaking. Indeed, anyone who has removed paint or varnish and the like from furniture or walls is cognizant of the tedium, expense, and hazards of the endeavor.
In particular, the removal or application of materials from and to overhead surfaces presents even further difficulties and hazards. For example, anyone who has prepared and painted a ceiling knows all too well the fatigue engendered by the simple task of holding up a scraper or brush for any period of time, no matter how short. Adding to this, the scraping or brushing motion required results in an arm- and back-aching experience. Further, there are the dangers of materials to be applied or removed dropping from the ceiling onto the person or floor. In total, the job is extremely tiring, unpleasant, and hazardous. In the context of large buildings having ceilings of extensive area, the job is difficult. Add to this the dangers of exposure to asbestos and the job becomes extremely dangerous as well.
Therefore, there is clearly a strong need for devices and systems which will alleviate the difficulties and dangers of the removal and application of materials from surfaces, particularly overhead surfaces, and increase the speed and efficiency of the processes.